1. Field of the Invention
The present invention relates to electrical connectors, and more particularly to a cable connector plug used in a connector for transmitting audio signals or other signals.
2. Discussion of the Related Art
FIG. 4 shows a side cross-sectional view of a conventional cable connector plug 10. The cable connector plug 10 includes a first metallic contact 11, a second metallic contact 12, a third metallic contact 13, a fourth metallic contact 14, and a plurality of insulators 15. The metallic contacts 11, 12, 13, 14 are insulated from each other by the insulators 15.
The first contact 11 includes a contact portion 110, an extension portion 111 extending rearwardly from the contact portion 110 along an axis of the cable connector plug 10, and a rear portion 112 extending rearwardly from the extension portion 111. The extension portion 111 includes a first columnar portion 1111, a neck portion 1112, and a second columnar portion 1113. The neck portion 1112 interconnects the first columnar portion 1111 and the second columnar portion 1113. A diameter of the first columnar portion 1111 is greater than that of the second columnar portion 1113. A shape of the neck portion 1112 is a conical frustum that tapers from an end at the first columnar portion 1111 to an opposite end at the second columnar portion 1113. A combined length of the first columnar portion 1111 and the neck portion 1112 along the axis is usually 2.4 millimeters.
The second and third contacts 12, 13 each include an annular contact portion 120, 130, a cylindrical extension portion 121, 131 extending rearwardly from the contact portion 120, 130, and a rear portion 122, 132 extending rearwardly from the extension portion 121, 131. The fourth contact 14 includes a cylindrical contact portion 140, an annular extension portion 141 extending rearwardly from the contact portion 140, and a rear portion 142 extending from the extension portion 141. The extension portions 111, 121, 131, 141 of the first, second, third, and fourth contacts 11, 12, 13, 14 are coaxially arranged in that order from an inside to an outside of the cable connector plug 10. Accordingly, diameters of the extension portions 111, 121, 131, 141 increase in that sequence. The contact portions 110, 120, 130, 140 of the contacts 11, 12, 13, 14 are insulated from each other by a plurality of annular insulating ring portions (not labeled) of the insulators 15. The extension portions 111, 121, 131, 141 of the contacts 11, 12, 13, 14 are insulated from each other by a plurality of cylindrical portions (not labeled) of the insulators 15.
The rear portion 112 of the first contact 11 extends rearwardly beyond the insulators 15 for soldering with a first wire (not shown) of a cable (not shown). A rearmost part of the rear portion 122 of the second contact 12 is exposed for soldering with a second wire (not shown) of the cable. The other part of the rear portion 122 of the second contact 12 is embedded between the corresponding insulators 15. A rearmost part of the rear portion 132 of the third contact 13 is exposed for soldering with a third wire (not shown) of the cable. The other part of the rear portion 132 of the third contact 13 is embedded between the corresponding insulators 15. The rear portion 142 of the fourth contact 14 extends perpendicularly outward from the insulator 15 that is between the third and fourth contacts 13, 14, and is for soldering with a fourth wire (not shown) of the cable.
Generally, the neck portion 1112 of the first contact 11 angularly connects with the second columnar portion 1113, such that an angular junction is defined where the neck portion 1112 connects with the second columnar portion 1113. When force is applied to the contact portion 110 at angles close to 90 degrees relative to the axis, pressure received by the neck portion 1112 and the second columnar portion 1113 accumulates at a circular periphery of the angular junction. If the pressure is greater than a critical pressure of the extension portion 111, the extension portion 111 is liable to break at the angular junction where the neck portion 1112 connects with the second columnar portion 1113. Therefore, the mechanical strength and durability of the cable connector plug 10 is limited.
What is needed, therefore, is a new cable connector plug which can overcome the above-described shortcomings.